Griseofulvin with high specific surface area



United States Patent Ofi 3,330,727 Patented July 11, 1967 3,330,727 GRISEOFULVIN WITH HIGH SPECIFIC SURFACE AREA Kenneth Arthur Lees, Northwood England, assignor to Glaxo Laboratories Limited, Greenford, Middlesex, England, a British company No Drawing. Continuation of application Ser. No.

103,224, Apr. 17, 1961. This application July 15,

1964, Ser. No. 382,923

6 Claims. (Cl. 167-65) This application is a continuation of copending application Ser. No. 103,224, filed Apr. 17, 1961, now abandoned.

This invention is concerned with improvements in or relating to the antibiotic griseofulvin.

Griseofulvin has recently found considerable use in the treatment of various human and animal diseases. The substance is generally given by internal administration, particularly by mouth but may also be applied topically.

In the majority of preparations the griseofulvin is present in solid form and, for example, for oral administration, the antibiotic may be incorporated in a tablet, capsule or pill or be given in a suspension in some convenient liquid base.

My researches have shown that the uptake of griseofulvin into the blood stream following oral administration of solid griseofulvin is dependent upon the physical nature of the solid. I have thus found that by reducing the particle size of the solid to smaller dimension than the material hitherto used, the peak blood level following oral administration of a given dose is raised. The effect of raising the extent of uptake into the blood of a given dose of griseofulvin also has the important advantage that a detectable concentration is maintained in the blood for a longer period.

Investigation has thus shown that improved uptake of solid griseofulvin may be secured by preparing griseofulvin in particulate form having a specific surface area of at least 0.75X cm. g.

Preferably also the solid griseofulvin should be in crystalline or micro-crystalline form, as distinct from amorphous form.

The invention accordingly comprises solid griseofulvin in particulate form, preferably in crystalline or microcrystalline form, having a specific surface area of at least 0.75 X10 cm. /g.

Whilst good results are obtained with solid griseofulvin having a specific surface area of at least 075x10 cm. g., even better results are obtained by a further particle size reduction below 0.9)(10 cm. /g., and better still below 1.2)(10 cmF/ g.

A still further improvement in absorption has been noted in some cases by reduction in particle size below 1.5 and in some cases 1.7 10 cm. g.

The improved form of griseofulvin in accordance with the invention may be formulated for oral administration in any convenient form with the aid of suitable pharmaceutical carriers or excipients. Such preparations may be in solid form, for example, tablets, capsules, pills, dragees or other unitary form, or as powders or granules. For the production of such preparations, conventional carriers or excipients may be used as desired.

Orally administra-ble preparations may also be formulated in liquid form as suspensions or dispersions in a suitable carrier, which may be of an aqueous or oily nature. Such preparations may include other excipients such as suspending agents e.g. colloids, wetting agents, dispersing agents, sweetening agents or fiavouring agents as desired.

The production of griseofulvin in small particle size in accordance with the invention may be achieved in various ways. A method of obtaining such material by direct crystallisation which has been found to be particularly convenient is described in Shaw et a1. application Ser. No. 103, 343, filed Apr. 17, 1961. Griseofulvin of small particle size can also be obtained directly by the spray-drying of a solution of griseofulvin in a suitable solvent, e.g. chloroform or acetone, although the material so produced may be of an amorphous nature instead of the desired crystalline or mgicrocrystalline form. The spray dried material may comprise particles of the desired small particle size admixed with larger particles in which case classification of the particles to give a fraction of the desired size is necessary.

Alternatively, griseofulvin of large particle size obtained, for example, by the milling of griseofulvin produced by conventional techniques may be further size-reduced e.g. by passage through a suitable colloid mill or vibratory mill.

To illustrate the advantages of the improved form of griseofulvin according to the invention, a number of experiments were conducted in human volunteers to determine the average uptake of griseofulvin upon oral administration of tablets containing the antibiotic in different particle sizes.

For these experiments groups of six volunteers were asked to swallow either two or four tablets of the griseofulvin sample under test, each tablet containing 2.50 mg. of antibiotic.

The various forms of griseofulvin were thus tested at two dosages i.e. 0.5 g. and 1 g. Blood samples were taken by veni-puncture at 2, 4, 6, 8 and 26 hours and in some groups 50 hours after dosing, and were assayed in duplicate spectrophotofluorometrically. The results are shown in the following table:

TAB LE Hours After Administration Specific Surface Area Dose, g. Volunteer 0.4X10 cmF/g 0. 5 1 0. 4 0. 7 0. 7 0. 6 0. 1 2 C 0. 5 0. 5 0. 3 0. 2 3 0 0. 6 0. 6 0. 4 0. 3 4 *C 0. 7 0. 7 1. 0 0. 3 5 0 0 0. 3 0. 3 0. 2 6 0. 3 0. 5 0. 5 0. 3 0. 3

Average 0. 18 0. 5O 0. O. 48 0. 23 0.8)(10 cmfl/g 0. 5 7 1.0 1.0 0.6 0. 5 0.3 8 0. 7 1.2 1. 2 1. 0 0. 5 9 0. 5 0. 6 0. 3 0. 3 0 10 1. 0 0. 8 0. 6 0. 5 0 11 0. 3 0. 5 0. 5 0. 2 0 12 0.7 1.2 1.1 0.8 0.6

Average 0. 0. 88 0. 71 0. 56 0. 23

TABLECntinued 3 S 0 u 556 4 3 n 43334 2 4 2 233 2 0 0 0000 00 Q nnunn O L0 U 0 fiw 0 0 0n0 0 0 0 5 u us u u n n 0 n n m 7 5 3 0 2 0% G4. 6 2 349878 6 44 2226 3 4 880627 0 638789 0 0 0000 ow QOWQQQOW Q 000 000 Q 0 QLLHWLO L 0 0 0 0 QQ 0 n 0 .1 t m 3 3 l 7 3 7 357838 7 028718 4 079788 8 O 8165 6 311322 5 802095 0 8 LQOWQOQ flw LLLLZQ L LQQQOWU 0 IOQLOO 0 LnLLLZL L nU LLLLfiw L .1 M

U 3 3 5 3 3 M 2677fl d8 w 49943- 4 109988 9 7 9Qv7- 6 181370 3 043214 0- H 6 L0 0 0 0 fiw Hm 0 0 LLp mflw L LLU O fiw0 0 0000 00 0 LLLLLL L LLLLAZQ L A r u 0 a 0 0 5 O 3 H 183053 0 5759HPI-5 0 109901 0 9 0695 6 510 -642 5 154514 3 LO LLO L L LUKLLnLO L LLQQLL L OOLQOO Ow LOMLLLL L LLLLZO L 0 I 3 0 773740 8 853488 7 666730 126414 6 238269 0 992395 "1 2 UQLOWQL 0 0 0 00 1 .0 Ow nmfimfiwQflwL 0 LQQQLO 0 LLQLQQ L nu LL1 .0 O L 1 345678 901234 n 507890 123456 739012 345678 W 111111 lqhfllonquoy n 222223 333333 33444 444444 t n 0 u n u u 0 7 u n 5 5 g n X 1 1 0 0 m l 1 e S 0 D a e r A n u n n n u u w a e a. a a e e e a. e a e g e e r r FL I r r S m e m o m e m e m 0 m e w 0 V C V C V 0 V G V C V m m A m A m. A m A o A m A e l 1 l l 1 1 D X X X X X X S B J J 0 0 1 1 l 1 "C Contaminated blood sample tube.

6H d 6 6 U S r ab e P b 3 a t m s m 0 H H .1 wem L11V1 men w d mm m o UC .4 u l Cuma a n v ne h t nTOw a.r em in ca 0 ui c fen .1 i u w Htah n a u r nW On h IOU re o fitd 5 4 way of example only a description of a g small particle size griseofulvin by the griseofulvin from a normal production batch with an approximate specific surface area of for wet milling the slurry, a greater charge and reduced 0.4 10

sing a vibratory mill grinding time can be obtained by u cm. g. is mixed with distilled water to produce ansferred to a suitable with sintered alumina grinding media.

a percent slurry. The slurry is tr rindin container, consisting em, The following examples of suitable oral preparations a of a polyethylene jar grinding media to a level given by way of of small particle size griseofulvin are illustration only:

or porcelain pot charged with just below the surface of the slurry. The grinding media onsist of porcelain or marble balls, cylinders of /2" diameter prepared from sintered alumina or stainmay c In the formulation of the following preparations crystalline griseofulvin having a specific surface area of less steel balls or rods. The container holding the griseofulvin slurry and grinding char grinding mill,

ge is clamped to a vibratory with controlled amplitude o vibration allowed to operate ent on the specific surface and the product required 54 M2 n 8. Z 1 6 8 m a .1 m a a 2 x D.. E ..H efi S( un m a 0 m r m Oe fs s m mGS 1 b a T O 6 ddmwm n ei 6 Cpl ne m cdmog H q f mm ft m m.m r ma d m 0 0m .l Htdoc P um a m a c m mm T eral hours to several days, and durin it may be necessary t add further small quantities of distilled water to the slurry to reduce viscosity as the particle The fine particle Size griseofulvin is size of the griseofulvin decreases. Samples are wtihdrawn of the Starch The remaining Starch is used in t from the slurry at intervals, vacuum dried a of a 10 percent starch paste as the surface area determinations carried out,

particle s the mm e uh granulating medium.

until the desired btained. The slurry is then removed from g mill diluted with distilled water and dis- The damp granules are passed through a No. 12 mesh ize is o rindin sieve, dried under vacuum at a temperature not exceedmg 25 C. and passed through a No. 16 mesh sieve. The magnesium stearate is blended with the dried granules which are t charged into a Buchner funnel or porcelain filter fitted with a suitable filter paper. Vacuum is applied to remove 7 O the water. Recycling of the filtrate is employed to obtain maximum yield. Alternatively the into a suitable centrifuge. The

en compressed at 300 mg. per tablet.

slurry can be discharged grinding media and container are repeatedly rinsed with distil led water to obtain Griseofulvin (fine particle size) maximum yield. The wet cake is then removed from the Fill into hard gelatine capsules, size 00.

Water to produce 100.

Dissolve the preservative in the available water, heated to 90 C. Add the sugar, and disperse the methyl cellulose in the hot solution by slowly sprinkling it onto the surface of the liquid, stirred by vortex action. When the sugar is dissolved, allow the mixture to stand overnight to cool and pass through an homogeniser. Absorb the peppermint oil into the griseofulvin powder and blend in the sweetening agents and lecithin. Make a thick slurry of the powders with some of the homogenised mixture and refine by passing through a colloid mill. Dilute the refined slurry with the remaining vehicle, make up to volume and mix well.

I claim:

1. A product consisting of crystalline griseofulvin in particulate form, said griseofulvin having a specific surface area of at least 0.75 X cm. g.

2. Griseofulvin as claimed in claim 1 having a specific surface area of at least 0.9 10 cm. /g.

3. Griseofulvin as claimed in claim 1 having a specific surface area of at least 1.2 1O cmF/g.

4. A pharmaceutical preparation comprising crystalline griseofulvin in the form of particles having a specific surface area of at least 0.75 10 cm. g. and a pharmaceutical carrier, such preparation being adapted for oral administration.

5. A pharmaceutical tablet comprising crystalline griseofulvin in the form of particles having a specific surface area of at least 0.75 10 cm. /g. and at least one tableletting excipient.

6. A pharmaceutical capsule containing crystalline griseofulvin in the form of particles having a specific surface area of at least 075x10 cm. g.

References Cited FOREIGN PATENTS 5/1958 Great Britain.

OTHER REFERENCES HENRY R. IILES, Primary Examiner. NICHOLAS RIZZO, Examiner. ALEX MAZEL, Assistant Examiner.

(Third Edition) 2 3 NITED STATES PATENT .()F

CERTIFICATE OF CORREcfrION.

Par-8mm. 3,330,727

Dated July 11 1-9'6'7 Inventor) Kenneth Arthur Lees It is certified that error appears in the aboveand that said Letters Patent are hereby corrected as shown below:

Column 1, between lines 9 and 10, insert Claims priority, application Great Britain, April 19-;- 1960,

Signed and sealed this 14th day of January 1975.

(SEAL) Attest:

MCCOY M. GIBSON JR.

C. MARS LL ANN Attesting Officer HA D Commissioner of Patents identified patent 

4. A PHARMACEUTICAL PREPARATION COMPRISING CRYSTALLINE GRISEOFULVIN IN THE FORM OF PARTICLES HAVING A SPECIFIC SURFACE AREA OF AT LEAST 0.75X10**4 CM.2/G. AND A PHARMACEUTICAL CARRIER, SUCH PREPARATION BEING ADAPTED FOR ORAL ADMINISTRATION. 